/Engine/Source/Runtime/Engine/Classes/Engine/AssetManager.h
Finds all the referencers for a set of packages. Recursively will get all the referencers up to the max depth
static void GetAllReferencersForPackage ( [TSet](API\Runtime\Core\Containers\TSet)< [FAssetData](API\Runtime\CoreUObject\AssetRegistry\FAssetData) > & OutFoundAssets, const [TArray](API\Runtime\Core\Containers\TArray)< [FName](API\Runtime\Core\UObject\FName) > & InPackageNames, int32 MaxDepth )